After reading the thread title, I thought this was the challenge, that anybody can try to figure out if they feel like:

Set up a 3-player game where, on turn three, you have the choice to make either of the other two players win

That's pretty easy. Just have the player on your right to do a 3-pile ending with a 1-point lead and have them play a Masq which allows you to pass the other player an Estate which is worth 2 points thanks to Pasture.